I suppose tr is a more core method and thus probably a faster way to replace things within a given file.
However tr can only replace equal amounts of characters. meaning...
2 characters can only be ...

I have file test_output_archive.svd with some Dollar signs ($).
I have generated a shell script Replace_dollar_pound.sh with cat command to replace dollar symbol with Pound (£)
script is working on ...

I need to replace all unwanted spaces in all files from the current directory and from directories from the current directory (recursive search).
I define the unwanted spaces the spaces and tabs that ...